MariTide Results: How Much Weight Amgen’s Monthly Shot May Deliver

In its phase 2 trial, MariTide produced up to about 20% average weight loss over a year in people with obesity, and importantly, the weight loss hadn’t leveled off by the end of the study. That combination (strong results from a once-monthly injection, with room to go further) is what has generated excitement around Amgen’s candidate. MariTide is investigational and not FDA approved. Here’s a closer look at the numbers and what they suggest.

The Headline Numbers

MariTide’s mid-stage results come from a phase 2 trial published in the New England Journal of Medicine in 2025. In people with obesity but without type 2 diabetes, MariTide produced up to about 20% average weight loss at 52 weeks, compared with roughly 2.6% on placebo. In people who had both obesity and type 2 diabetes, the average was up to about 17%, versus roughly 1.4% on placebo.

As with other weight-loss drugs, people with diabetes lost somewhat less than those without, a consistent pattern across this class.

The Detail That Stands Out

The most striking part of MariTide’s results isn’t just the amount of weight lost, but the trajectory. At 52 weeks, the weight loss curve had not plateaued, meaning participants were still losing weight when the study ended. This matters because it suggests the roughly 20% figure may understate what MariTide could achieve with longer treatment. Many weight-loss drugs reach a plateau somewhere around a year; MariTide apparently hadn’t yet. Consider a hypothetical patient a year into treatment who is still steadily losing: their final result could end up higher than the one-year number implies, which is part of why the phase 3 trials are so anticipated.

Why the Monthly Dosing Is Part of the Story

These results are notable partly because they come from a once-monthly injection. Delivering roughly 20% weight loss with just 12 injections a year (or potentially fewer) is a meaningful convenience advantage over weekly drugs. Beyond weight, MariTide also improved blood sugar substantially in people with diabetes and produced favorable changes in cardiometabolic markers like waist circumference and blood pressure. The main side effects were gastrointestinal (nausea, vomiting), mostly mild and concentrated around the first dose, and reduced when the dose was escalated gradually.

How It Compares

MariTide’s roughly 20% at 52 weeks puts it in the upper tier of weight-loss drugs, competitive with the strongest approved and investigational options. Direct comparisons are tricky because trials differ in length and design, and the fact that MariTide’s weight loss hadn’t plateaued makes head-to-head comparisons at fixed timepoints potentially misleading. What’s clear is that a once-monthly drug producing this level of weight loss would be a significant addition to the field, which is why it’s advanced to phase 3.

Frequently Asked Questions

How much weight can you lose on MariTide?

In its phase 2 trial, people with obesity lost up to about 20% of their body weight over 52 weeks, and those with obesity and diabetes lost up to about 17%. Because the weight loss hadn’t plateaued at one year, longer trials may show larger results.

Is MariTide more effective than weekly injections?

Its roughly 20% weight loss is competitive with the strongest weekly drugs, and it achieves this with once-monthly dosing. Whether it’s more effective overall will become clearer from phase 3 trials and longer follow-up, since its weight loss was still increasing at one year.

Is MariTide available yet?

No. MariTide is investigational and not FDA approved. It has completed phase 2 and advanced to phase 3 testing, so it’s only available through clinical trials. TrimRx does not offer it.

To focus on treatments available today, you can explore the options available to you now with a licensed provider.

This information is for educational purposes and is not medical advice. MariTide is investigational and not FDA approved; details and timelines may change. Consult a healthcare provider before starting any medication. Individual results may vary.